<p>As I recall, following the kernel upgrade, I was trying to update my system from the command line, using aptitude, and it warned of a conflict and asked for confirmation to replace grub-efi-amd64 with grub-pc, which I denied. I think update-manager queried about a "partial upgrade", so I thought it was simply a problem of one package lagging behind the others as when installing a beta distribution upgrade.</p>
<p>From the time I installed Ubuntu on this system, grub-pc had been listed as a "missing recommend" in synaptic.</p>